The John Day Dam is located in the state of Oregon on the Columbia River. In 2020 the Army Corps of Engineers put a repair job out to bid to address a variety of situations, including leaks that were occurring in a number of the galleries (openings or passageways within the dam). The general contractor that won the bid brought Spokane, Washington’s Talisman Construction Services in for the leak seal portion of the job.

Powerful Polymers

The Army Corp of Engineers specified a flexible polyurethane for the specialty waterproofing due to the fact that it would be injected into dynamic joints and cracks (joints and cracks that contract and expand with weather conditions).

The technicians from Talisman Construction Services chose Spetec PUR F400 from Alchemy-Spetec. This product features 100% elongation. If you install a rigid product in a dynamic joint or crack is will fail at the first movement. In addition to its flexible nature, Spetec PUR F400 is also hydrophobic. Hydrophobic polyurethanes have excellent chemical resistance and superior longevity. In addition, Spetec F400 features a field adjustable set time (when you have cold water, with varying volumes, this is essential so you can either penetrate small cracks with a slower set time or shut down gushing leaks with a faster set time).

The Bureau of Reclamation and the Army Corp of Engineers have approved Spetec PUR F400 for use on their structures. This durable repair material has been successfully installed in many of their dams and locks.

Painless Procedures

One of the classic rules of grouting cracks and joints is to pull off the crack or joint half the thickness of the wall and drill at a 45° angle. However, when you get over 3’ thick it is not necessary to pull off the crack or joint more than 1.5’. The crew followed these guidelines when injecting the resin.

On thicker structures leaking cold water at high volumes, it is imperative to be able to adjust the set times in the field. Gen ACC is the accelerator for Spetec PUR F400 and is added at a ratio of 1% all the way up to 10%. The more you add the quicker the product polymerizes. The crew adjusted the set times according to properties of each leak.

They also soaked AP Oakum in Spetec PUR F400, and packed it into the wider cracks and high volume leaks. Depending on the situation, the oakum is sometimes packed in before the injection or packed in simultaneously as a second crew member fills the void with the first crew member is injecting the resin.

Rapid Results

Within a matter of days, the leaks in the galleries were successfully remediated. The general contractor was then able to move on to other parts of their project, on budget and on schedule.

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